The excess enthalpies of (carbon dioxide + cyclohexane) at 308.15, 358.15, and 413.15 K from 7.50 to 12.50 MPa

• Published in: The Journal of chemical thermodynamics 1983, Vol.15 (12), p.1151-1157
• Main Authors: Christensen, J.J., Christensen, S.P., Schofield, R.S., Faux, P.W., Harding, P.R., Izatt, R.M.
• Format: Article
• Language: English
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1016/0021-9614(83)90006-X

The excess molar enthalpies H m E for (carbon dioxide + cyclohexane) were measured in the vicinity of their critical locus and in the supercritical region. Mixtures at 308.15 K and at 7.50 MPa show very exothermic mixing and a region where H m E varies linearly with mole fraction x while at 10.50 and 12.50 MPa they show only moderately endothermic mixing. Mixtures at 358.15 and 413.15 K and at all pressures studied except for 358.15 K and 12.50 MPa have an exothermic section in the cyclohexane-rich region, a linear section which starts at a mole fraction x corresponding very closely to that of the minimum value of H m E, and an endothermic section in the carbon-dioxide-rich region. The H m E results exhibiting a linear section allow the determination of values for the vapor and liquid equilibrium-phase compositions. The changes observed in the excess enthalpy with both pressure and temperature are discussed in terms of liquid-vapor equilibrium and critical constants for (carbon dioxide + cyclohexane).